The articles of religion are some of them practical and some of them speculative. Now, though both sorts consist in the knowledge of truth, yet these terminate simply in the understanding, those influence the will and the manners. Speculative opinions, therefore, and articles of faith (as they are called) which are required only to be believed, cannot be imposed on any church by the law of the land. For it is absurd that things should be enjoined by laws which are not in men’s power to perform. And to believe this or that to be true, does not depend upon our will…. But will (some say) lets men at least profess that they believe. A sweet religion, indeed, that obliges men to dissemble and tell lies, both to God and man, for the salvation of their souls! If the magistrate thinks to save men thus, he seems to understand little of the way of salvation. — from A Letter Concerning Toleration

John Locke (1632–1704) is an English philosopher, physician, and essayist who is considered the father of political liberalism. One of the first proponents of British empiricism — which asserts that all knowledge is obtained through sensory experience — Locke has had a tremendous influence on both American and continental history. The Scottish and French Enlightenment as well as the American founders all trace their political philosophical thought in part back to Locke. His Letter Concerning Toleration is considered in many ways a culmination of Locke’s various strands of thought.